Acute respiratory distress syndrome in trauma patients: ICU mortality and prediction factors

Early time-course of respiratory mechanics, mechanical power and gas exchange in ARDS patients

PURPOSE

To describe the clinical course of ARDS during the first three days of mechanical ventilation, to compare ventilatory setting, respiratory mechanics and gas exchange variables collected during the first three days of mechanical ventilation between patients who survived and died during intensive care unit (ICU) stay and to investigate the variables associated with mortality at ICU admission and throughout the first three days of mechanical ventilation.

MATERIALS AND METHODS

Prospective observational study. Mechanically ventilated ARDS patients were studied at ICU admission and for the following three days. Univariate logistic regression models were performed for PaO2/FiO2 ratio, driving pressure and alveolar dead space fraction and for mechanical power and mechanical power ratio.

RESULTS

Mechanical power ratio was higher in non survivors at ICU admission and over time; PaO2/FiO2 ratio was higher in survivors with a similar behavior over time in the two groups while alveolar dead space fraction was similar at ICU admission and over time between groups. Mechanical power ratio was the only physiological variable which remained consistently associated with ICU mortality throughout the study.

CONCLUSIONS

The alteration in oxygenation, dead space, and mechanical power ratio should be assessed not at intensive care admission, but during the first days of mechanical ventilation to better predict outcome.

Clinical epidemiology and mortality on patients with acute respiratory distress syndrome (ARDS) in Vietnam

BACKGROUND

The clinical epidemiology and disease prognosis in patients with acute respiratory distress syndrome (ARDS) have not yet been fully elucidated in Vietnam.

METHODS

We conducted a retrospective observational study at a national tertiary hospital in Hanoi, Vietnam. Participants were adult patients (age ≥18 years) who were admitted and diagnosed with ARDS during 2015-2017. Data on patients' general and clinical conditions, radiographic findings, ventilator settings, gas exchange, and treatment methods were collected and compared between survivors and non-survivors. Risk factors for mortality were assessed using logistic regression analysis.

RESULTS

Among 126 eligible patients with ARDS admitted to the central tertiary hospital in Vietnam, we observed high mortality (57.1%). Of the total patients, 91.3% were transferred from local hospitals with a diagnosis of severe pneumonia and then diagnosed with ARDS at the central hospital. At the time of admission, 53.2% of patients had severe ARDS, 37.3% had moderate ARDS, and 9.5% had mild ARDS. The mean (standard deviation) sequential organ failure assessment (SOFA) score was 9.5 (3.4) in non-survivors and 7.4 (3.4) in survivors (p = 0.002). Although there was no significant difference in PaO2/FiO2 on admission between non-survivors and survivors, that on day 3 after admission was significantly different (p = 0.002). Logistic regression revealed that PaO2/FiO2 on day 3 [odds ratio (OR), 1.010; 95% confidence interval (CI), 1.003-1.017], length of stay in a local hospital before admission to the central hospital (OR, 1.122; 95% CI, 1.042-1.210) due to stable condition, and SOFA score on Day 1 (OR, 0.842; 95% CI, 0.708-1.002) were independent factors in patient survival.

CONCLUSIONS

Patients with ARDS admitted the central tertiary hospital had severe illness and high mortality. Most patients were transferred from local hospitals. Improvements in human, medical, and sociological resources in local will contribute to reducing the mortality of ARDS in Vietnam.

Correlation between Extravascular Lung Water and Oxygenation in ALI/ARDS Patients in Septic Shock: Possible Role in the Development of Atelectasis?

This study aimed to evaluate the relationship between PaO2/FiO2 ratio and extravascular lung water in septic shock-induced acute respiratory distress syndrome in a prospective observational clinical trial.

Twenty-three patients suffering from sepsis induced acute respiratory distress syndrome were recruited. All patients were ventilated in pressure control/support mode. Haemodynamic parameters were determined by arterial thermodilution (PiCCO) eight hourly for 72 hours. At the same time blood gas analyses were done and respiratory parameters were also recorded. Data are presented as mean±SD. For statistical analysis Pearson's correlation test, and analysis of variance (ANOVA) was used respectively.

Significant negative correlation was found between extravascular lung water and PaO2/FiO2 (r= −0.355, P<0.001), and significant positive correlation was shown between extravascular lung water and PEEP (r=0.557, P<0.001). A post-hoc analysis was performed when “low” PEEP: <10 cmH2O and “high” PEEP: (10 cmH2O PEEP was applied, and neither the oxygenation, nor the driving pressure or the PaCO2 differed significantly, but the extravascular lung water showed significant difference when “high” or “low” PEEP was applied (13±5 vs 9±2 ml/kg respectively, P=0.001).

This study found significant negative correlation between extravascular lung water and PaO2/FiO2. The mechanism by which extravascular lung water affects oxygenation is unknown but the significant positive correlation between PEEP and extravascular lung water shown in this trial suggests that the latter may have a role in the development of alveolar atelectasis.

High Levels of Soluble Triggering Receptor Expressed on Myeloid Cells-Like Transcript (TLT)-1 Are Associated With Acute Respiratory Distress Syndrome

We have previously demonstrated that elevated levels of soluble triggering receptor expressed on myeloid cells-like transcript 1 (sTLT-1) modulate sepsis-induced inflammation and positively correlate with disseminated intravascular coagulation (DIC). Here, we evaluate the clinical implications of plasma sTLT-1 in acute respiratory distress syndrome (ARDS), which is common in sepsis patients. Soluble TLT-1 levels in the plasma of ARDS patients (n = 20) were determined by slot blot analysis and were compared with clinical parameters to identify significant associations. For comparisons to ARDS, we also measured sTLT-1 levels in matched healthy controls (n = 20). Of the 20 plasma samples evaluated from patients with ARDS, 60% were diagnosed with sepsis and 40% were diagnosed with septic shock. The white blood cells (WBCs) of patients with ARDS were found to be significantly elevated over healthy controls with a mean of 13 k/µL over 6.2 k/µL, respectively. The mean plasma levels of sTLT-1 were 148.4 pg/mL ± 16.52 in the patient cohort and 92.45 pg/mL ± 17.12 in the control group ( P = .02). No statistically significant correlations were found between plasma levels of sTLT-1 and WBCs, sepsis, septic shock or acute physiologic, and chronic health evaluation II scores. A statistically significant inverse correlation (r² = .25, P < .05) was found between plasma sTLT-1 and peripheral platelet counts in patients with ARDS. Increased levels of sTLT-1 in ARDS patients suggest that TLT-1 may mediate the pathobiology of ARDS. Moreover, our data are the first to demonstrate a specific platelet marker in the development of ARDS due to sepsis.

High-frequency power of heart rate variability can predict the outcome of thoracic surgical patients with acute respiratory distress syndrome on admission to the intensive care unit: a prospective, single-centric, case-controlled study

BACKGROUND

The morbidity and mortality of acute respiratory distress syndrome (ARDS) remains high, and the strategic focus of ARDS research has shifted toward identifying patients at high risk of mortality early in the course of illness. This study intended to identify the heart rate variability (HRV) measure that can predict the outcome of patients with ARDS on admission to the surgical intensive care unit (SICU).

METHODS

Patients who had lung or esophageal cancer surgery were included either in the ARDS group (n = 21) if they developed ARDS after surgery or in the control group (n = 11) if they did not. The ARDS patients were further stratified into survivors and non-survivors subgroups according to their outcomes. HRV measures of the patients were used for statistical analysis.

RESULTS

The mean RR interval (mRRI), high-frequency power (HFP) and product of low-/high-frequency power ratio tidal volume and tidal volume (LHR*VT) were significantly lower (p < 0.05), while the normalized HFP to VT ratio (nHFP/VT) was significantly higher in the ARDS patients (p = 0.011). The total power (TP), low-frequency power (LFP), HFP and HFP/VT were all significantly higher in the non-survived ARDS patients, whereas Richmond Agitation-Sedation Scale (RASS) was significantly lower in the non-survived ARDS patients. After adjustment for RASS, age and gender, firth logistic regression analysis identified the HFP, TP as the significant independent predictors of mortality for ARDS patients.

CONCLUSIONS

The vagal modulation of thoracic surgical patients with ARDS was enhanced as compared to that of non-ARDS patients, and the non-survived ARDS patients had higher vagal activity than those of survived ARDS patients. The vagal modulation-related parameters such as TP and HFP were independent predictors of mortality in patients with ARDS on admission to the SICU, and the HFP was found to be the best predictor of mortality for those ARDS patients. Increased vagal modulation might be an indicator for poor prognosis in critically ill patients following thoracic surgery.

Factors determining outcomes in adult patient undergoing mechanical ventilation: A "real-world" retrospective study in an Indian Intensive Care Unit

Background:

Characteristics of patients admitted to intensive care units with respiratory failure (RF) and undergoing mechanical ventilation (MV) have been described for particular indications and diseases, but there are few studies in the general Intensive Care Unit (ICU) population and even lesser from developing countries.

Objective:

This study aims to study clinical characteristics, outcomes, and factors affecting outcomes in adult patients with RF on MV admitted to ICU.

Methods:

A retrospective study of medical records of all patients admitted to ICU between January 1, 2015, and March 31, 2016. Patients receiving MV for more than 6 h were included in the study. Patients younger than 12 years were excluded. Data were recorded of all patients receiving MV during this period regarding demographics, indications for MV, type and characteristics of ventilation, concomitant complications and treatment, and outcomes. Data were recorded at the initiation of MV and daily all throughout the course of MV. The main outcome measure was all-cause mortality at the end of ICU stay.

Results:

Of the 500 patients admitted to the ICU during the period of the study, a total of 122 patients received MV (and were included in study) for mean (standard deviation [SD]) duration of 4 (3.4) days. The mean (SD) stay in ICU and hospital was 4.49 (3.52) and 6.4 (3.6), respectively. Overall mortality for the unselected general ICU patients on MV was 67.21% while that for ARDS patients was 76.1%. The main factors independently associated with increased mortality were (i) pre-MV factors: age, Apache II scores, heart failure (odds ratio [OR], 1.42; 95% confidence interval [CI], 0.54–3.73; P < 0.001); (ii) patient management factors: positive end-expiratory pressure (OR, 2.69; 95% CI, 0.84–8.61; P < 0.001); (iii) Factors occurring over the course of MV: PaO₂/FiO₂ ratio < 100 (OR, 1.66; 95% CI, 0.67–4.11; P < 0.001) and development of renal failure (OR, 2.33; 95% CI, 2.05–2.42; P < 0.001) and hepatic failure (OR, 2.07; 95% CI, 1.91–2.24; P < 0.001) after initiation of MV.

Conclusions:

Outcomes of patients undergoing MV are dependent on various factors (including patient demographics, nature of associated morbidity, characteristics of the MV received, and conditions developing over course of MV) and these factors may be present before or develop after initiation of MV.

Role of biomarkers in acute traumatic lung injury

In severely injured patients severe thoracic trauma is common and can significantly influence the outcome of these critically ill patients by increased rates of mainly pulmonary complications. Furthermore, patients who sustained thoracic trauma are at increased risk for Acute Lung Injury (ALI) or Adult Respiratory Distress Syndrome (ARDS). Therapeutic options are limited, basically consisting of prophylactic antibiotic therapy and changing patient's positions. It is known, that ALI and ARDS differ clinically and pathobiologically from ALI/ARDS caused by other reasons, but the exact pathology remains elusive. Due to that no reliable predictive or surveillance biomarkers could be established for clinical diagnosis and identification of patients at high risk for acute traumatic lung injury. Nevertheless, there are plenty of promising markers that need to be further elucidated in larger case numbers and multicenter studies. This article sums up the recent status of those promising clinical biomarkers.

Epidemiological profile of acute respiratory distress syndrome patients: A tertiary care experience

Background:

Acute respiratory distress syndrome (ARDS) is seen in critically ill patients. Its etiological spectrum in India is expected to be different from that seen in western countries due to the high prevalence of tropical infections.

Aim:

To study the epidemiological profile of ARDS patients.

Setting:

A tertiary care hospital in Karnataka, India.

Materials and Methods:

Retrospective analysis of 150 out of the 169 ARDS patients diagnosed during 2010–2012. Data collected included the clinical features and severity scoring parameters.

Results:

The mean age of the study population was 42.92 ± 13.91 years. The causes of ARDS included pneumonia (n = 35, 23.3%), scrub typhus (n = 33, 22%), leptospirosis (n = 11, 7.3%), malaria (n = 6, 4%), influenza (H1N1) (n = 10, 6.7%), pulmonary tuberculosis (n = 2, 1.3%), dengue (n = 1, 0.7%), abdominal sepsis (n = 16, 10.7%), skin infection (n = 3, 2%), unknown cause of sepsis (n = 18, 12%), and nonseptic causes (n = 15, 10%). A total of 77 (51.3%) patients survived, 66 (44%) expired, and 7 (4.7%) were discharged against medical advice (AMA). Preexisting comorbidities (46) were present in 13 survivors, 19 nonsurvivors, and four discharged AMA. History of surgery prior to the onset of ARDS was present in one survivor, 13 nonsurvivors, and one discharge AMA. Mean Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE III, and Sequential Organ Failure Assessment scores in survivors were 9.06 ± 4.3, 49.22 ± 14, and 6.43 ± 2.5 and in nonsurvivors 21.11 ± 7, 86.45 ± 23.5, and 10.6 ± 10, respectively.

Conclusion:

The most common cause of ARDS in our study was pneumonia, but a large percentage of cases were due to the tropical infections. Preexisting comorbidity, surgery prior to the onset of ARDS, higher severity scores, and organ failure scores were more frequently observed among nonsurvivors than survivors.

The impact of cardiac dysfunction on acute respiratory distress syndrome and mortality in mechanically ventilated patients with severe sepsis and septic shock: an observational study

PURPOSE

Acute respiratory distress syndrome (ARDS) is associated with significant mortality and morbidity in survivors. Treatment is only supportive, therefore elucidating modifiable factors that could prevent ARDS could have a profound impact on outcome. The impact that sepsis-associated cardiac dysfunction has on ARDS is not known.

MATERIALS AND METHODS

In this retrospective observational cohort study of mechanically ventilated patients with severe sepsis and septic shock, 122 patients were assessed for the impact of sepsis-associated cardiac dysfunction on incidence of ARDS (primary outcome) and mortality.

RESULTS

Sepsis-associated cardiac dysfunction occurred in 44 patients (36.1%). There was no association of sepsis-associated cardiac dysfunction with ARDS incidence (p= 0.59) or mortality, and no association with outcomes in patients that did progress to ARDS after admission. Multivariable logistic regression demonstrated that higher BMI was associated with progression to ARDS (adjusted OR 11.84, 95% CI 1.24 to 113.0, p= 0.02).

CONCLUSIONS

Cardiac dysfunction in mechanically ventilated patients with sepsis did not impact ARDS incidence, clinical outcome in ARDS patients, or mortality. This contrasts against previous investigations demonstrating an influence of nonpulmonary organ dysfunction on outcome in ARDS. Given the frequency of ARDS as a sequela of sepsis, the impact of cardiac dysfunction on outcome should be further studied.

Factors affecting mortality of critical care trauma patients

BACKGROUND

Critically-ill trauma patients have a high mortality.

OBJECTIVE

To study the factors affecting the mortality of ICU trauma patients treated at Al-Ain Hospital, United Arab Emirates (UAE).

METHODS

All trauma patients who were admitted to the ICU were prospectively collected over three years (2003-2006). Univariate and multivariate analysis were used to compare patients who died and who did not. Gender, age, nationality, mechanism of injury, systolic blood pressure and GCS on arrival, the need for ventilation, presence of head or chest injuries, AIS for the chest and head injuries and the ISS were studied.

RESULTS

There were 202 patients (181 males). The most common mechanism of injury was road traffic collisions (72.3 %). The overall mortality was 13.9%. A direct logistic regression model has shown that factors that affected mortality were decreased GCS (p < 0.0001), mechanism of injury (p = 0.004) with burns having the highest mortality, increased age (p = 0.004), and increased ISS (p = 0.02). The best GCS that predicted mortality was 5.5 while the best ISS that predicted mortality was 13.5.

CONCLUSION

Road traffic collision is the most common cause of serious trauma in UAE followed by falls. Decreased GCS was the most significant factor that predicted mortality in the ICU trauma patients.

Predictors of pulmonary failure following severe trauma: a trauma registry-based analysis

BACKGROUND

The incidence of pulmonary failure in trauma patients is considered to be influenced by several factors such as liver injury. We intended to assess the association of various potential predictors of pulmonary failure following thoracic trauma and liver injury.

METHODS

Records of 12,585 trauma patients documented in the TraumaRegister DGU® of the German Trauma Society were analyzed regarding the potential impact of concomitant liver injury on the incidence of pulmonary failure using uni- and multivariate analyses. Pulmonary failure was defined as pulmonary failure of ≥ 3 SOFA-score points for at least two days. Patients were subdivided according to their injury pattern into four groups: group 1: AIS thorax < 3; AIS liver < 3; group 2: AIS thorax ≥ 3; AIS liver < 3; group 3: AIS thorax < 3; AIS liver ≥ 3 and group 4: AIS thorax ≥ 3; AIS liver ≥ 3.

RESULTS

Overall, 2643 (21%) developed pulmonary failure, 12% (n= 642) in group 1, 26% (n= 697) in group 2, 16% (n= 30) in group 3, and 36% (n= 188) in group 4. Factors independently associated with pulmonary failure included relevant lung injury, pre-existing medical conditions (PMC), sex, transfusion of more than 10 units of packed red blood cells (PRBC), Glasgow Coma Scale (GCS) ≤ 8, and the ISS. However, liver injury was not associated with an increased risk of pulmonary failure following severe trauma in our setting.

CONCLUSIONS

Specific factors, but not liver injury, were associated with an increased risk of pulmonary failure following trauma. Trauma surgeons should be aware of these factors for optimized intensive care treatment.

Diffuse alveolar damage of the lungs in forensic autopsies: assessment of histopathological stages and causes of death

Introduction. Diffuse alveolar damage (DAD) is a morphological prototype of acute interstitial pneumonia. Hospital autopsies or open-lung biopsies are used to monitor common alveolar damage and hyaline membrane (HM) development histopathologically. The aim of this study was to detect histopathological profiles and frequency of DAD and HM in adult forensic autopsies. Materials and Methods. In total, 6813 reports with histopathological samples in 12,504 cases on which an autopsy was performed between 2006 and 2008 were investigated. Sixty-six individuals >18 years of age who were diagnosed with DAD were included. Hematoxylin- and eosin-stained lung preparations were reexamined in line with the 2002 American Thoracic Society/European Respiratory Society idiopathic interstitial pneumonia consensus criteria. Results. Histopathological examination revealed that 50 cases (75.7%) were in the exudative phase and 16 (24.2%) were in the proliferative phase. Only the rate of alveolar exudate/oedema in exudative phase cases (P = 0.003); those of alveolar histiocytic desquamation (P = 0.037), alveolar fibrosis (P = 0.017), chronic inflammation (P = 0.02), and alveolar fibrin (P = 0.001) in proliferative cases were significantly higher. The presence of alveolar fibrin was the only independent variable in favour of proliferative cases (P = 0.016). Conclusion. The detection of all DAD morphological criteria with the same intensity is not always possible in each case. Forensic autopsies may provide a favourable means for expanding our knowledge about acute lung damage, DAD, and interstitial lung disease.

Changing epidemiology of trauma deaths leads to a bimodal distribution

Injury mortality was classically described with a trimodal distribution, with immediate deaths at the scene, early deaths due to hemorrhage, and late deaths from organ failure. We hypothesized that the development of trauma systems has improved prehospital care, early resuscitation, and critical care and altered this pattern. This population-based study of all trauma deaths in an urban county with a mature trauma system reviewed data for 678 patients (median age, 33 years; 81% male; 43% gunshot, 20% motor vehicle crashes). Deaths were classified as immediate (scene), early (in hospital, ≤4 hours from injury), or late (>4 hours after injury). Multinomial regression was used to identify independent predictors of immediate and early versus late deaths, adjusted for age, gender, race, intention, mechanism, toxicology, and cause of death. Results showed 416 (61%) immediate, 199 (29%) early, and 63 (10%) late deaths. Compared with the classical description, the percentage of immediate deaths remained unchanged, and early deaths occurred much earlier (median 52 vs 120 minutes). However, unlike the classic trimodal distribution, the late peak was greatly diminished. Intentional injuries, alcohol intoxication, asphyxia, and injuries to the head and chest were independent predictors of immediate death. Alcohol intoxication and injuries to the chest were predictors of early death, while pelvic fractures and blunt assaults were associated with late deaths. In conclusion, trauma deaths now have a predominantly bimodal distribution. Near elimination of the late peak likely represents advancements in resuscitation and critical care that have reduced organ failure. Further reductions in mortality will likely come from prevention of intentional injuries and injuries associated with alcohol intoxication.

Short-term prognosis of critically ill surgical patients: the impact of duration of invasive organ support therapies

PURPOSE

We wanted to identify the importance of the duration of invasive ventilation and of renal replacement therapy for short-term prognosis of surgical patients treated in an intensive care unit (ICU).

METHODS

We analyzed adult patients (n = 1462) who had an ICU length of stay of more than 4 days and who were followed up until the end of the short-term phase after ICU admission. Duration of different invasive therapies was evaluated by constructing specific vectors that tested effects of time-dependent variables on outcome after a lag time of 7 days.

MEASUREMENTS AND MAIN RESULTS

Eight hundred eight patients (56.6%) were still alive at the end of the short-term phase. During the short-term phase, 85.3% of the 1462 patients required invasive ventilation, and 16.1%, a continuous renal replacement therapy. Besides the underlying disease and disease severity at ICU admission, the need for invasive ventilation or renal replacement therapy was associated with poorer outcome. Duration of invasive ventilation shortened survival if treatment lasted for more than 11 days (nonlinear association). In contrast, duration of renal replacement therapy was unimportant for short-term prognosis.

CONCLUSION

Prolonged duration of invasive ventilation but not of renal replacement therapy is inversely related to short-term survival.

Changes in plasma fibronectin isoform levels predict distinct clinical outcomes in critically ill patients

INTRODUCTION

Concentrations of the total pool of fibronectin in plasma (TFN), and the subset of this pool that contains the alternatively spliced EDA segment (A(+)FN), are both affected by disease processes, and the latter pool has gained a reputation as a biomarker for vascular injury. We therefore wished to determine if changes in either FN pool correlate with clinical outcomes in critically ill individuals.

METHODS

We analyzed a database for 57 patients with major trauma (n = 33) or sepsis syndrome (n = 24) in which plasma levels of TFN and A(+)FN had been measured at intervals, along with clinical parameters. Logistic regression analysis was performed to detect associations between predictive variables and three clinical outcomes: 1) the acute respiratory distress syndrome (ARDS), 2) milder acute lung injury designated acute hypoxemic respiratory failure (AHRF), and 3) survival to hospital discharge.

RESULTS

An increase in plasma TFN during the first 24 hours of intensive care unit (ICU) observation was negatively associated with progression to ARDS (odds ratio 0.98 per 1 microgram (μg)/ml increase, 95% CI (0.97, 1.00)) and AHRF (OR 0.97 per 1 μg/ml increase, (0.95, 0.99)), whereas an increase in A(+)FN over the first 24 hours was positively associated with progression to AHRF (OR 1.65 per 1 μg/ml increase, (1.04, 2.62)). Additionally, the ratio of the partial pressure of oxygen in arterial blood (PaO(2)) to the percentage of oxygen in inspired air (FIO(2)) after 24 hours was positively associated with survival (OR 1.01 per 1 unit increase in ratio, (1.00, 1.03)), along with change in A(+)FN (OR 1.30 per 1 μg/ml increase, (0.90, 1.88)).

CONCLUSIONS

Different FN isoforms may constitute predictive covariate markers for distinct clinical outcomes in critically ill patients. The data also suggest that early TFN accumulation in the circulation may confer a clinical benefit to patients at risk for acute lung injury.

Significance of elevated cardiac troponin T levels in critically ill patients with acute respiratory disease

BACKGROUND

Elevations in cardiac troponin have prognostic importance in critically ill patients. However, there are no data addressing the independent association between troponin levels and mortality, adjusted for the severity of the underlying disease, in patients hospitalized for acute respiratory disorders. We investigated whether troponin T (cTnT) elevations are independently associated with in-hospital mortality in patients in the intensive care unit (ICU) admitted for severe and acute respiratory conditions. After adjusting for the severity of disease measured by the Acute Physiology, Age, and Chronic Health Evaluation (APACHE) III prognostic system, we evaluated short-term (30 days) and long-term (3 years) mortality.

METHODS

We studied the APACHE III database and cTnT levels from patients admitted consecutively to the ICU at Mayo Clinic, Rochester, Minnesota. Between January 2001 and December 2005, 2078 patients with respiratory conditions had cTnT measured at ICU admission. In-hospital, short-term (30 days) and long-term (3 years) all-cause mortality were determined.

RESULTS

Of the study patients, 878 (42.3%) had elevated cTnT and 1200 patients (57.7%) had undetectable cTnT. During hospitalization, 1.1% of the patients with troponin T <0.01 ng/mL died compared to 21% of those with troponin T ≥0.01 ng/mL (P <.0001). At 30 days, mortality was 18.6% in patients with elevations of cTnT and 1.5% in patients without elevations of cTnT (P <.0001). The Kaplan-Meier probability of survival at 1-year follow-up was 71.0%, at 2-year follow-up was 48.3%, and 3-year follow-up was 39.4% with troponin T ≥0.01 ng/mL and at 1-year follow-up was 98.8%, at 2-year follow-up was 97.2%, and at 3-year follow-up was 95.5% with troponin T <0.01 μg/L (P <.0001). After adjustment for severity of disease and baseline characteristics, cTnT levels remained associated with in-hospital, short-term and long-term mortality (P <.0001).

CONCLUSIONS

In patients admitted to the ICU for respiratory disorders, cTnT elevations are independently associated with in-hospital, short-term and long-term mortality.

Circulating angiopoietin 2 correlates with mortality in a surgical population with acute lung injury/adult respiratory distress syndrome

There are few blood biomarkers predictive of mortality in adult respiratory distress syndrome (ARDS), and none that currently serve as therapeutic targets. Here, we ask whether a circulating protein angiopoietin 2 (Ang2) correlates with severity of lung injury and mortality in a surgical intensive care unit cohort with acute lung injury (ALI)/ARDS. Tie 2 is a tyrosine kinase receptor expressed on endothelial cells. One ligand, angiopoietin 1, phosphorylates Tie 2 and stabilizes adult vasculature. An alternate ligand, Ang2, serves as a context-dependent antagonist and disrupts barrier function. Previously, our laboratory detected high circulating Ang2 levels in septic patients and a correlation with low Pa(O2)/F(IO2). In this study, daily plasma was collected in 63 surgical intensive care unit patients. Eighteen patients met clinical criteria for ALI or ARDS. The median Ang2 at admission in patients who never developed ALI/ARDS was 3.7 ng/mL (interquartile range [IQR], 5.6; n = 45). The Ang2 on the day a patient met criteria for ALI/ARDS was 5.3 ng/mL (IQR, 6.7) for survivors (n = 11) and 19.8 ng/mL (IQR, 19.2) for nonsurvivors (n = 7; P= 0.004). To explore the mechanism of high Ang 2 leading to increased permeability, plasma from patients with ALI was applied to cultured lung endothelial cells and found to disrupt normal junctional architecture. This effect can be rescued with the Tie 2 agonist angiopoietin 1. A patient's convalescent (low Ang2) plasma did not disrupt junctional architecture. Although further studies with larger sample sizes will be needed to confirm these results, high Ang2 in critically ill patients with ALI/ARDS is associated with a poor outcome. These data, coupled with our cell culture experiments, suggest that antagonism of Ang2 may provide a future novel therapeutic target for ARDS.

Early markers of acute respiratory distress syndrome development in severe trauma patients

PURPOSE

The aim of the study was to identify early risk factors for development of acute respiratory distress syndrome (ARDS) in severe trauma patients.

MATERIALS AND METHODS

This was a prospective observational study of 693 severe trauma patients (Injury Severity Score >or=16 and/or Revised Trauma Score <or=11) in 17 hospitals in a Spanish region of 8 million inhabitants from July 2002 to December 2002.

RESULTS

Acute respiratory distress syndrome developed in 6.9% of patients who were more severely ill with higher APACHE II (P < .001) and Injury Severity Score (P = .002) scores vs patients not developing ARDS. Acute respiratory distress syndrome development was associated (P < .001) with fractures of femur (International Classification of Diseases, Ninth Revision [ICD-9] codes 820, 821), tibia (ICD-9 code 823), humerus, and pelvis, with a number (>or=2) of long bone fractures, and with chest injuries (rib/sternal fracture [ICD-9 code 807] and hemo/pneumothorax [ICD-9 code 860/861]). Patients with ARDS required more colloids (P = .005) and red blood cell units (P = .02) than patients without ARDS during the first 24 hours. Multivariate analysis showed that ARDS was related to chest trauma diagnosis (ICD-9 code 807) (odds ratio [OR], 3.85), femoral fracture (OR, 3.16), APACHE II score (OR, 1.05), and blood transfusion during resuscitation (OR, 1.32).

CONCLUSIONS

Risk of ARDS development is related to the first 24-hour admission variables, including severe physiologic derangements and specific ICD-9-classified injuries. Blood transfusion may play an independent role.

Predictors of mortality in ARDS patients referred to a tertiary care centre: a pilot study

BACKGROUND AND OBJECTIVE

In order to identify parameters predicting intensive care unit mortality in patients transferred to a specialized tertiary centre because of progressive acute respiratory distress syndrome, an observational pilot study was carried out involving 94 patients.

METHODS AND RESULTS

Forty-one patients (43.6%) died. Survival was defined as intensive care unit discharge. Survivors were younger (32.0 +/- 11.8 vs. 39.1 +/- 12.4 yr, P = 0.008), at admission they had a lower acute physiology and chronic health evaluation (APACHE) II score (21.7 +/- 5.4 vs. 25.4 +/- 5.2, P = 0.0009), higher PaO2/FiO2 (122 +/- 79 vs. 79 +/- 42 mmHg, P = 0.002), lower positive end-expiratory pressure (10.6 +/- 3.1 vs. 12.5 +/- 3.7 cmH2O, P = 0.02) and a lower Murray score (2.8 +/- 0.63 vs. 3.0 +/- 0.62, P = 0.04). No differences were observed for tidal volumes and peak inspiratory pressures. Days of hospitalization and mechanical ventilation prior to transferral were not related to survival. Multivariate analysis of variables assessed on admission detected only differences for age (P = 0.014) and APACHE II (P = 0.005). Odds ratio was 1.06 (95% confidence interval (CI): 1.013-1.119) for age and 1.21 (CI: 1.059-1.381) for APACHE II. Multivariate analysis of changes in respiratory parameters, APACHE II and Murray score during the first 3 days after transferral revealed a significant difference only for positive end-expiratory pressure (P < 0.008). Corresponding odds ratio was 2.40 (CI: 1.25-4.58) for an increase of 1 cmH2O/24 h.

CONCLUSION

Age-related mortality in this small, but highly selected group of patients with established ARDS increased early in life even in a population with an overall mean age of 35.1 yr. APACHE II was the only clinical predictor for mortality on admission. The need for a substantial increase in positive end-expiratory pressure after transferral markedly reduced the chance to survive.

Increased glomerular permeability and pulmonary dysfunction following major surgery: correlation of microalbuminuria and PaO/FiO ratio

BACKGROUND

The aim of our trial was to evaluate the ability of microalbuminuria as an indicator of outcome and to investigate its relationship with the postoperative respiratory dysfunction in the initial postoperative period in a high-risk patient group.

METHODS

In our prospective, observational study patients were consecutively recruited following elective oesophagectomy, total gastrectomy, Whipple-resection of the pancreas and liver resection due to tumour removal. Microalbuminuria (expressed as urine albumin:creatinine ratio, M:Cr) was measured before (tp), and after surgery (t0, t6, t24, t48, t72). Multiple Organ Dysfunction Scores were monitored on ICU admission than daily (t1, t2, t3). For statistical analysis, Wilcoxon's rank-sum test, Mann-Whitney's U-test, receiver operating characteristic curve analysis and Spearman's rho test were used as appropriate.

RESULTS

One hundred and forty patients (118 survivors and 22 non-survivors) were recruited. Significantly higher Multiple Organ Dysfunction Scores were observed in non-survivors throughout the study period (P < 0.001). Microalbuminuria (Cr) increased significantly (P < 0.01) on admission to the ICU (t0) compared with the preoperative levels, but levels returned to normal within 6 h and remained so for the rest of the study. There was a significant difference between survivors and non-survivors at t0 (P < 0.01). However the ROC curve indicated that M:Cr is not a reliable descriptor of outcome. Comparison of Cr values with the PaO2/FiO2 ratio showed an inverse relationship on admission, which remained so for t24 and t48.

CONCLUSION

M:Cr measured on admission to the ICU was significantly higher in non-survivors than in survivors, and also showed an inverse relationship with the PaO2/FiO2 ratio following extended abdominal surgery. However, on admission, M:Cr did not discriminate survivors from non-survivors. Further studies are required to evaluate the prognostic value of this test for postoperative patients with risk of respiratory failure.

Effect of acute lung injury and acute respiratory distress syndrome on outcome in critically ill trauma patients

OBJECTIVE

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are known to be associated with increased mortality and costs in trauma patients. We estimated the independent impact of these conditions on mortality and cost, beyond the severity of injury with which they are correlated.

DESIGN

One-year prospective cohort.

PATIENTS AND SETTING

All trauma patients admitted to the intensive care unit in a level I center were evaluated daily for ALI/ARDS using the American-European Consensus Conference definition.

MEASUREMENTS AND MAIN RESULTS

The main outcome measures were hospital mortality and costs. Logistic regression was used to model hospital mortality in relation to the presence of ALI and ARDS, adjusting for trauma severity (Injury Severity Score), Acute Physiology Score, and age. Hospital costs were modeled using multivariable linear regression. Of the 1,296 trauma patients surviving beyond the first day, 4% experienced ALI (defined as Pao2/Fio2 of 201-300 mm Hg) and 12% had ARDS (Pao2/Fio2 < or = 200 mm Hg). The crude relative risk of mortality was 2.24 (95% confidence interval, 0.92-5.45) in patients with ALI and 3.84 (95% confidence interval, 2.41-6.13) in patients with ARDS compared with those without ALI/ARDS. However, there was no association of mortality with ALI (relative risk, 0.99; 95% confidence interval, 0.29-3.36) or with ARDS (relative risk, 1.23; 95% confidence interval, 0.63-2.43) after adjustment for age, Injury Severity Score, and Acute Physiology Score. Among patients of comparable age, severity score, and length of stay, median cost was 20% to 30% higher for those with ALI/ARDS.

CONCLUSIONS

There is no additional mortality associated with ALI/ARDS above and beyond the factors that can be measured at intensive care unit admission. Therefore, mortality in trauma patients is explained by injury severity at admission and is not affected by the subsequent occurrence of ALI/ARDS. Nonetheless, ALI/ARDS was associated with increased intensive care unit stay and hospital cost, independent of trauma severity.

Acute acalculous cholecystitis after trauma: a prospective study

OBJECTIVE

The purpose of this study was to identify risk factors for the development of acute acalculous cholecystitis (AAC) and useful criteria to facilitate the decision to perform cholecystectomy.

METHODS

This was a prospective study of patients with an Injury Severity Score (ISS) > or = 12 requiring intensive care for > 4 days (n = 255), divided into three groups by ultrasound: AAC (n = 27), hydropic gallbladder (n = 37), and normal gallbladder (n = 191). Multivariate analysis was conducted for trauma scores and laboratory and intensive care unit (ICU) data and complemented by logistic regression analysis.

RESULTS

Three factors sufficiently define the risk for AAC: ISS, heart rate, and units of packed red blood cells required at ICU admission. All patients who underwent cholecystectomy (n = 21) had both highly pathologic ultrasound and major clinical symptoms, and all had histologically verified AAC. There was no significant difference in daily laboratory data between patients with and without AAC.

CONCLUSION

Patients with a high ISS who are tachycardic and have required several units of packed red blood cells at ICU admission should be monitored early by ultrasound. When ultrasound is highly pathologic together with major clinical symptoms, cholecystectomy should be performed. Daily laboratory data are of no additional value regarding the decision to perform cholecystectomy.

Lack of effect of prophylactic N-acetylcysteine on postoperative organ dysfunction following major abdominal tumour surgery: a randomized, placebo-controlled, double-blinded clinical trial

Sepsis and respiratory dysfunction leading to multiple system organ failure remains the leading cause of postoperative morbidity and mortality following major surgical procedures. It has been suggested the oxygen free radicals might play a pivotal role in this process. The aim of this study was to investigate whether short-term infusion of N-acetylcysteine (N-acetylcysteine), a potent antioxidant, administered before and during extensive abdominal surgery, could ameliorate the progression of early postoperative organ dysfunction and improve oxygenation. Out of the 93 patients, 47 received N-acetylcysteine and 46 were given placebo in a randomized, controlled, double-blinded fashion. Patients received N-acetylcysteine (150 mg.kg-1 bolus followed by a continuous infusion of 12 mg.kg-1.h-1) or the same volume of placebo (5% dextrose) during surgery. Treatment effect on organ function was assessed by organ dysfunction scores according to physiological parameters of six main organ systems: respiratory, cardiovascular, renal, hepatic, haematological and central nervous system. The scores were obtained on admission, then daily during the first three postoperative days. For statistical analysis Mann-Whitney U and Chi-squared tests were used. There was no significant difference between the two groups in any of the six organ dysfunction parameters, length of intensive care stay, days of mechanical ventilation and mortality. Our results do not support the routine use of N-acetylcysteine as a prophylactic measure during surgery, and reinforce previous evidence which challenges the indication of N-acetylcysteine in the critically ill.

Epidemiology and outcome of acute respiratory failure in intensive care unit patients

OBJECTIVES

To summarize the prevalence of various forms of acute respiratory failure in acutely ill patients and review the major factors involved in the outcome of these patients.

DATA SOURCES AND SELECTION

MEDLINE search for published studies reporting the prevalence or outcome for patients with acute respiratory failure and cited reference studies and abstracts from a recent international meeting in the intensive care medicine field.

DATA SYNTHESIS AND EXTRACTION

From the selected articles, information was obtained regarding the prevalence of acute respiratory failure, including acute respiratory distress syndrome and acute lung injury as defined by the North American-European Consensus Conference, the outcome, and the factors influencing mortality rates in this population of patients.

CONCLUSIONS

The prevalence of acute respiratory failure varies according to the definition used and the population studied. Nonsurvivors of acute respiratory distress syndrome die predominantly of respiratory failure in <20% of cases. The relatively high mortality rates of acute lung injury/acute respiratory distress syndrome are primarily related to the underlying disease, the severity of the acute illness, and the degree of organ dysfunction.

Influence on outcome of ventilator-associated pneumonia in multiple trauma patients with head trauma treated with selected digestive decontamination

OBJECTIVE

Ventilator-associated pneumonia is said to be associated with an increased mortality or a prolonged intensive care unit stay. In multiple trauma, the use of selective digestive decontamination has been reported to decrease morbidity and mortality associated with pneumonia. We performed a study to evaluate the attributable morbidity and mortality of ventilator-associated pneumonia in multiple trauma patients with head trauma treated with selective digestive decontamination.

DESIGN

Prospective, matched-paired, case-control study.

SETTING

Intensive care unit at a tertiary university hospital.

PATIENTS

During a 6-yr period, 324 consecutive multiple trauma patients with head trauma requiring mechanical ventilation for >48 hrs were prospectively followed for the development of VAP. Case-control matching criteria were as follows: 1) age difference within 5 yrs, 2) Glasgow coma scale within five categories, 3) injury severity score within 5 points, 4) APACHE II score within 5 points, 5) ventilation of control patients for at least as long as the cases. The selective digestive decontamination regimen was used in all patients (cases and controls): polymixin E, gentamicin, and amphotericin B. Systemic cefazolin (1 g three times a day) was given for the first 3 days of intensive care unit stay.

MEASUREMENTS AND MAIN RESULTS

Analysis was performed on 58 pairs that were matched with 100% of success The most common isolates recovered were Staphylococcus aureus (39%) and Haemophilus influenzae (22%). High-risk pathogens were rarely isolated: Pseudomonas aeruginosa (5.1%), Acinetobacter species (8.6%), and methicillin-resistant S. aureus (6.7%). The duration of mechanical ventilation and intensive care unit stay were increased in case patients (11.6 +/- 1.7 and 22.7 +/- 2.9 days, respectively) compared with control patients (9.4 +/- 1.3 and 16.8 +/- 2.9 days, respectively; p <.0006). Mortality was similar in both case (17%) and control (24%) patients.

CONCLUSION

Ventilator-associated pneumonia did not seem to increase mortality of multiple trauma patients with head trauma who received selective digestive decontamination. Whether or not this conclusion applied to trauma patients not receiving selective digestive decontamination should be evaluated in further studies.

Modulation of chemokine production in lung microvascular endothelial cells by dopamine is mediated via an oxidative mechanism

Serum concentrations of catecholamines are high in patients with sepsis or acute respiratory distress syndrome (ARDS). Because chemokines mediate the recruitment of neutrophils into inflammatory sites, we addressed the question of whether dopamine (DA) is able to influence chemokine production in endothelial cells under basal and proinflammatory conditions. To this end, lung microvascular endothelial cells (LMVEC) were stimulated or not for 24 h with the bacterial toxins lipopolysaccharide (LPS) (1 microg/ml) or lipoteichonic acid (LTA) (10 microg/ml) in the presence or absence of various concentrations of DA (1-100 microg/ml). Whereas under basal and stimulatory conditions, the addition of DA to endothelial cells dose-dependently increased IL-8 production, the production of ENA-78 and Gro-alpha was significantly inhibited (P < 0.01). This effect could still be demonstrated when the cells were stimulated for up to 3 h with LPS before DA administration. Similar findings were detected for the mRNA expression of these chemokines. The influence of DA on chemokine production was not receptor mediated and could be prevented by antioxidants or radical scavengers. Moreover, addition of H(2)O(2) to endothelial cells gave results similar to those observed with DA stimulation, suggesting a pivotal role for reactive oxygen species in DA-mediated modulation of chemokine production in endothelial cells. Our data thus demonstrate that DA administration results in the induction of oxidative stress, with profound effects on endothelial chemokine production.